The aim of this study was to retrospectively analyze 18F-FDG positron emission tomography/computed tomography (18F-FDG PET/CT) metabolic variables, programmed death-ligand 1 (PD-L1) and phosphorylated signal transducer and activator of transcription 3 (p-STAT3) tumor expression, and other factors as predictors of disease-free survival (DFS) in patients with lung adenocarcinoma (LUAD) (stage IA-IIIA) who underwent surgical resection. We still lack predictor of immune checkpoint (programmed cell death-1 [PD-1]/PD-L1) inhibitors. Herein, we investigated the correlation between metabolic parameters from 18F-FDG PET/CT and PD-L1 expression in patients with surgically resected LUAD.Seventy-four patients who underwent 18F-FDG PET/CT prior to treatment were consecutively enrolled. The main 18F-FDG PET/CT-derived variables were primary tumor maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). Surgical tumor specimens were analyzed for PD-L1 and p-STAT3 expression using immunohistochemistry. Correlations between immunohistochemistry results and 18F-FDG PET/CT-derived variables were compared. Associations of PD-L1 and p-STAT3 tumor expression, 18F-FDG PET/CT-derived variables, and other factors with DFS in resected LUAD were evaluated.All tumors were FDG-avid. The cutoff values of low and high SUVmax, MTV, and TLG were 12.60, 14.87, and 90.85, respectively. The results indicated that TNM stage, PD-L1 positivity, and high 18F-FDG PET/CT metabolic volume parameters (TLG ≥90.85 or MTV ≥14.87) were independent predictors of worse DFS in resected LUAD. No 18F-FDG metabolic parameters associated with PD-L1 expression were observed (chi-square test), but we found that patients with positive PD-L1 expression have significantly higher SUVmax (P = .01), MTV (P = .00), and TLG (P = .00) than patients with negative PD-L1 expression.18F-FDG PET/CT metabolic volume parameters (TLG ≥90.85 or MTV ≥14.87) were more helpful in prognostication than the conventional parameter (SUVmax), PD-L1 expression was an independent predictor of DFS in patients with resected LUAD. Metabolic parameters on 18F-FDG PET/CT have a potential role for 18F-FDG PET/CT in selecting candidate LUAD for treatment with checkpoint inhibitors.

This paper proposes “implied stochastic volatility models” designed to fit option-implied volatility data and implements a new estimation method for such models. The method is based on explicitly linking observed shape characteristics of the implied volatility surface to the coefficient functions that define the stochastic volatility model. The method can be applied to estimate a fully flexible nonparametric model, or to estimate by the generalized method of moments any arbitrary parametric stochastic volatility model, affine or not. Empirical evidence based on S&P 500 index options data show that the method is stable and performs well out of sample.

Employing a large sample of 7246 firms across 38 economies from 2000 to 2013, we show a positive relation between foreign institutional ownership (FIO) and firms' speed of leverage adjustment. This positive relation is concentrated for over-leveraged firms that need to decrease financial leverage to rebalance their capital structures. We validate our findings using a 2SLS regression and a DiD estimation to exploit the exogenous variations in FIO generated by the inclusion of MSCI membership and the passage of the JGTRRA. These results suggest that foreign institutional investors play an important monitoring role in mitigating agency conflicts between shareholders and managers. Overall, this paper lends support to the dynamic trade-off theory.

Institutional cross-owners, specifically institutional investors with significant stakes in multiple firms in the same industry, are becoming increasingly common in the United States. In this paper, we investigate and find that the presence of institutional cross-owners facilitates a firm's financing of its investment opportunities, consistent with institutional cross-owners reducing the adverse selection concerns of those who provide capital for the investment opportunities. We then examine the conditions under which the presence of institutional cross-owners is likely to more significantly reduce adverse selection and thereby have even more of a positive effect on the financing of investment opportunities. We document that relative to transient institutional cross-owners, dedicated institutional cross-owners facilitate more financing of investment opportunities. We also find that institutional cross-owners facilitate the financing of investment opportunities even more for firms with greater dependence on external financing, those with an opaque financial reporting environment, and those with more product market competition. Our paper offers novel insight into how a firm can benefit from the presence of institutional cross-owners.